Machine for cutting circular plates



(No Model.) 1

'S. TRETHEWEY. MACHINE FOR GUTTING CIRCULAR PLATES.

No. 429,072. Patented May 27, 1890.

4 l 1 1 ET u UNITED STATES PATENT OFFICE.

SAMUEL TRETHEIVEY, OF PITTSBURG, PENNSYLVANIA.

MACHINE FOR CUTTING CIRCULAR PL ATES.

SPECIFICATION forming part of Letters Patent No. 429,072, dated May 2'7,1890.

Application filed July 10, 1889. Serial No. 317,037. (No model-l To allwhom it may concern.-

Be it known that I, SAMUEL TRETHEWEY, a resident of Pittsburg, in thecounty of Allegheny and State of Pennsylvania, have in vented a new anduseful Improvement in Machines for Cutting Circular Plates; and I dohereby declare the following to be a full, clear, and exact descriptionthereof.

My invention relates to what are known as rotary shears for cuttingplate metal, these shears being applicable to the cutting of eitheroircularplates or of straight or other shaped plates, according as themetal is fed to the cutting-knives, though the shears are generallyemployed in connection with the cutting of circular plates.

To enable others skilled in the art to make and use my invention, I willdescribe the same more fully, referring to the accompanying drawings, inwhich- Figure 1 is a side view of a shearing-machine embodying myinvention. Fig. 2 is a longitudinal central section through thecutting-knives. Fig. 3 is a cross-section on the line 3 3, Fig. 1. Fig.4 is a cross-section on the line 4 4, Fig. 1; and Fig. 5 is across-section on the line 5 5, Fig. 1.

Like letters of reference indicate like parts in each.

In the shearing-machine shown embodying my invention, a is the machinebody or frame, having a bearing or head 1) bolted at one end thereof,and c the sliding block carrying'the clamp d, said block being made adjustablein the machine-frame by any suitable means, that shown in thedrawings consisting of a hand-wheel o, carrying a bevel-gear engagingwith a bevel-pinion at the end of a revolving screw or threaded barpassing through the block a, these parts being shown in dotted lines.The head b is generally formed of a single casting, and as heretoforeconstructed has had the cutter-shaft journaled directly therein, thecutter-shaft being rotated by power applied through any suitable gearingto a shaft 6, Fig. 4, and thence through apinion e on that shaft to apinion f on the lower cutter-shaft f, from which power was transmittedthrough the pinion g to the upper cutter-shaft J. To the cutter-shafts fg, respectively, are secured the rotary cutter and knives f g vto oneside of the center of said bushing, so

that the cutter-shafts f g do not extend centrally through thecylindrical bearing h of the head, but eccentrically through the same.By this construction, by turning the eccentric bushings 7c the positionof the cutter shafts and the cutters in their relation to each other canbe changedas, for example, to take up wear in the cutter and so extendtheir life very materially, or to provide for the cutting of differentthicknesses of plate. This is clearly shown in the several figures ofthe drawings, as it is evident that by the turning of either bushing theshafts are drawn toward or from each other, and that a very accurate anddelicate adjustment of the cutting-knives can thus be obtained. At therear ends of the bushings 7c are the flanges Z, which are either formedwith or secured to said bushings, and are either made annular or, asshown, have a series of notches Z there in, to provide for turning thebushings with a suitable wrench, it only being necessary where it isdesired to adjust the bushings to grasp the one or the other bushingwith a wrench and impart a slight turn thereto, when the position of thecutter-shaft passing through such bearing is immediately changed withrelation to the other cutter-shaft. In order to hold these bushings inproper relative position during the operation of the machine, I employ awedge-block m, which passes between the flanges Z of the two bushings,and by wedging between them holds them firmly to the position to whichthey are adjusted, the block being forced to place by means of the boltm screwing into the head I), or passing through the same and held by abolt. This block m has the upper and lower edges thereof curved, asshown, corresponding to the curve of the flanges with which they engage,so increasing its surface contact with the bushings, and by forcing itbetween said flanges Z sufficient binding force is obtained to hold thebushings in the position to which they have been adjusted, no matterwhat strain may be brought upon the cutter-shaft.

In these rotary shearing-machines it is well known that a very severelongitudinal strain is brought upon the shafts and cutters, the strainon the one shaft being in the opposite direction to that on the other,according as the knives cut into the metal. This strain causes the rapidwearing of the parts, and to overcome this I provide steel disks, whichmay be properly hardened so as to prevent wear, these disks beingemployed either with the bushings or with the shafts the1nselves, asshown more clearly in Fig. 2. In the one case the disk 71. is placed infront of the bearing or body of the head, and is se' cured to acollar 1) by pins passing from the disk a into the same, the disk andplate rotating with the cutter, and the plate acting to take the wearbetween the cutter-shaft and the ordinary bearing of the machine. In theother case, as the flange Z of the bushing is interposed between the endof the head I) andthe rear end of the shaft, said flange Z being heldstationary'during the operation of the machine, I generally secure theplate on by pins to the pinion f, which is keyed to the shaft f, theplate rotating with the shaft and bearing against the flange I, sosustaining the end-thrusts and wea-rbetween it and the shaft.

\Vhere the shearing-knives are adjusted, as above set forth, it isevident that in some cases-such as where either or both of thecutter-shaf ts turn from a vertical line passing cent-rally through thehead-the cutting operation may be performed better where the plate to becut is not held by the clamp with its center on the central line on themachine, but that it is desirable to adjust the centerof the plateaccording to the position of the knives or according to the thickness ofthe plate to be cut. For this purpose I employ a screw-stop on the framea of the machine, as at 1', this stop passing through a suitablethreaded hole formedin the projecting lug .9, formed with or rigidlyattached to the maehine-frame, as shown in Figs. 1 and 5, and thescrew-stop engaging with the body of the clamp, so that as the clamp isthrown around in feeding a plate to the cutting-knives it comes againstthis stop and is held thereby rigidly in position during the cuttingopera tion. If, however, it is found better to slightly adjust thepivotal point of the clamp so as to cause the more even cuttingoperation of the shears, this can be accomplished through saidscrew-stop 1*, which provides for the delicate adjustment of the clampfound desirable under such circumstances.

Where a plate is to be cut, the knives are adjusted toward or from eachother, as found desirable, by turning the eccentric bushings it, so inthe manner above described eausin g the proper adjustment of the knives,the bushin gs being locked in place by the wedge-block m, engaging withthe flanges Z. \Vhere the plate is circular, after marking out thecircle to be formed and securing the plate in the clamp d, it is fed tothe shears, the clamp being adj usted longitudinally through the wheel aand connections to the block 0, and in case it is found desirable toadjust the plate so as to bring the center thereof either to or awayfrom a central line through the machine, as may be found most desirable,this is accomplished by the screw-stop r bearing upon the body of theflange, as fully shown in Figs. 1 and I) u ring the cutting operationthe strain and greatest frictional action are brought upon thehardened-steel disks n, which sustain such action and prevent wear, sothat the wearing-powers of the apparatus are largely increased.

\Vhat I claim as my invention, and desire to secure by Letters Patent,is

1. In rotary shears for cutting plate metal, the combination, with themachine-head, of the cylindrical bushings fitting therein and havingshaft-bearings extending longitudinally through the same and eccentricto or at one side of the center of such bushings, and having theadjusting-flanges Z at the ends of said bushings, and the wedge m,engaging with said flanges and holding the bushings in place,substantially as and for the purposes set forth.

2. In rotary shears for cutting plate metal, the combination, with themachine-body a, of the longitudinal ad justing-loek c, swinging clamp(I, mounted therein, and the screw-stop 0' on the machi lie-frame andengaging with the clamp, substantially as and for the purposes setforth.

In testimony whereof I, the said SAMUEL TRETHEWEY, have hereunto setmyhand.

SAMUEL TRETHE WEY.

Witn esses:

J. N. COOKE, Ron'r. D. Terran.

